has anybody got a clue about how the door sounds (opening AND closing) of Wolfenstein 3D could have been recorded? I really like those, but I have no imagination on how someone could possibly achieve that.

Sounds like one metal click, a metal bang, then a metal slide and two metal clicks. You could probably use recordings of a key entering a keyhole for the clicks and hitting a metal cabinet and sliding it over the floor. Slowing all of these down by about 50% would make them sound 'heavier'.

Wow that sounds pretty good, thanks for your suggestion. It sounds different, of course, but it sounds pretty realistic.

Btw, I am asking beacuse I need sounds like those for a game that I currently develop. The game not only contains a metal sliding door, but also a wooden sliding door. Do you have any suggestions what I could use for that? The problem is that I don't really know what a wooden sliding door might sound like. A creaking door sound might not fit. Maybe something more pulley-style?

You could just use these, slow them down or pitch-shift them down to make them appear "heavier"/"bigger". Alternatively one can do the same thing I suggested for the metal door with wooden door elements (the lock sounds were recorded on a wooden door with a metal lock by the way).

Just using the sound I made, perhaps speeding it up or pitch-shifting it up a bit or even leaving it as it is could also be used for the door.